C++ Hello World: Undefined symbols for architecture x86_64

Question

when I try to compile a simple hello world code I get some architecture error from gcc

$ vim test.cpp

#include <iostream>

int main()
{
  std::cout << "Hello World!" << std::endl;
  return 0;
}

$ gcc test.cpp -o test.o

Undefined symbols for architecture x86_64:
  "std::cout", referenced from:
      _main in ccyEpFri.o
  "std::basic_ostream<char, std::char_traits<char> >& std::operator<< <std::char_traits<char> >(std::basic_ostream<char, std::char_traits<char> >&, char const*)", referenced from:
      _main in ccyEpFri.o
  "std::basic_ostream<char, std::char_traits<char> >& std::endl<char, std::char_traits<char> >(std::basic_ostream<char, std::char_traits<char> >&)", referenced from:
      _main in ccyEpFri.o
  "std::basic_ostream<char, std::char_traits<char> >::operator<<(std::basic_ostream<char, std::char_traits<char> >& (*)(std::basic_ostream<char, std::char_traits<char> >&))", referenced from:
      _main in ccyEpFri.o
  "std::ios_base::Init::Init()", referenced from:
      __static_initialization_and_destruction_0(int, int) in ccyEpFri.o
  "std::ios_base::Init::~Init()", referenced from:
      __static_initialization_and_destruction_0(int, int) in ccyEpFri.o
ld: symbol(s) not found for architecture x86_64
collect2: error: ld returned 1 exit status

The gcc I have is here: /usr/local/bin/gcc

$ gcc --version

gcc (GCC) 4.9.2 20141029 (prerelease)
Copyright (C) 2014 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

System setup: Mac OSX yosemit 10.10.2 GCC from http://hpc.sourceforge.net/

My original gcc 4.2 (the default on mac) was giving me couldn't understand kern.osversion '14.1.0' That's why I went for http://hpc.sourceforge.net/

$ g++ test.cpp -o test.o ld: entry point (start) undefined. Usually in crt1.o for architecture x86_64 collect2: error: ld returned 1 exit status — Morteza Shahriari Nia, Feb 27 '15 at 20:12
@MortezaShahriariNia you on windows OS? Maybe you don't have the 64bit version of MinGW installed? — πάντα ῥεῖ, Feb 27 '15 at 20:16
What operating system? How did you get and installed your GCC? Please edit your question to improve it. — Basile Starynkevitch, Feb 27 '15 at 20:16
I'm running on OSX yosemite. I got the compiler from http://hpc.sourceforge.net/ — Morteza Shahriari Nia, Feb 27 '15 at 20:20
You should edit your question to improve it, not add some comment! — Basile Starynkevitch, Feb 27 '15 at 20:21
As I see, GCC is manually compiled. Have you compiled libstdc++ too? Is it available at default linker path? If not, you should use line like: $ g++ test.cpp -o test -L/path/to/dir-with-libstdc++.so — Vadim Prozorov, Feb 27 '15 at 20:22
@Vadim Prozorov: no, the OP downloaded some binary tarball.... — Basile Starynkevitch, Feb 27 '15 at 20:25
Then the last chance I see is to specify `-L/usr/local/lib`. And manually compile GCC if this way failed. — Vadim Prozorov, Feb 27 '15 at 20:28
Perhaps you have some [clang](http://clang.llvm.org/)? Then you could use it (at least to compile [GCC](http://gcc.gnu.org/) from source) — Basile Starynkevitch, Feb 27 '15 at 20:31
I do have CLang as part of xcode. due to some dependency issues it is suggested to stick to gcc. — Morteza Shahriari Nia, Feb 27 '15 at 20:35

score 2 · Answer 1 · answered Feb 27 '15 at 20:15

2

Use g++ instead of gcc.

g++ is a *nix-based C++ compiler. gcc is a compiler for C, C++, Objective-C, Fortran, Java, Ada, and Go. The libraries used are different. Your code will work with g++ not gcc.

answered Feb 27 '15 at 20:15

tourniquet_grab

792
9
14

Same error `$ g++ test.cpp -o mytestprog` ld: entry point (start) undefined. Usually in crt1.o for architecture x86_64 collect2: error: ld returned 1 exit status – Morteza Shahriari Nia Feb 27 '15 at 20:16
no, just error and stops. no file created or modified – Morteza Shahriari Nia Feb 27 '15 at 20:22

score 1 · Answer 2 · edited May 23 '17 at 12:06

You should compile with

g++ -Wall -Wextra -g  test.cpp -o mytestprog

then run ./mytestprog and use gdb for debugging it.

If that command does not work, you might add -v after g++ (to be shown what is happening), and it would be a symptom that your g++ was wrongly configured or installed. Of course, do a which g++ to be sure that the g++ is the one you want.

Read my hints here about compiling your GCC. I believe that the binaries you've got from http://hpc.sourceforge.net/ do not fit your operating system. I would suggest to carefully build, compile and install, GCC from its source code (downloadable via these mirrors). It probably is not very easy (for newbies). Be sure to build outside of the source tree. Read carefully the install instructions.

Same error $ g++ -Wall -Wextra -g test.cpp -o mytestprog ld: entry point (start) undefined. Usually in crt1.o for architecture x86_64 collect2: error: ld returned 1 exit status — Morteza Shahriari Nia, Feb 27 '15 at 20:14

C++ Hello World: Undefined symbols for architecture x86_64

2 Answers2